Abstract

In plants, the developmental dynamics of telomere length have only been studied in a few species to date. Contrasting results have been reported. To search for the pattern(s) operating in plants, a study of the telomere length was made in pearl millet. Telomere length in cells representing different developmental stages: a) embryo, b) leaves of 1-week-old seedlings, 1-month-old plants and boot leaf and c) germ cells (pollen) were compared. The presence of the consensus plant telomere repeat sequence (5′-TTTAGGG-3′) in pearl millet telomeres was first ascertained; the sensitivity of the sequences hybridizing with (TTTAGGG)4 oligonucleotide to time course Bal 31 exonuclease digestions were studied on dot blots and gel blots. The exonuclease digestion kinetics revealed the presence of the consensus telomere repeat sequence in pearl millet telomeres. The average telomere length (ATL) was measured from autoradiograms of Hae III digested DNA, hybridized with labelled (5'-TTTAGGG-3′)4 oligonucleotide using “UVI band” software. No significant difference in the average telomere length was observed between the embryo, leaves of 1-week-old seedlings, boot leaf and pollen. The ATL in leaves of 1-month-old plants was slightly higher. The results of the present investigation and analysis of the reports in the other plants suggest that there is an occasional increase in telomere length in some telomeres but no significant decrease due to loss during DNA replication

We thank Dr K Srinivas Rao, Long Island Jewish Medical Centre, Long Island, New York for initiating this research. We thank Professor Thomas D McKnight, Department of Biology, Texas A&M University for going through the manuscript and giving comments and professor K Subba Rao, Department of Biochemistry, University of Hyderabad, India for helping with the ATL measurements. KUD thanks the UGC special assistance programme (Phase III) of the Botany Department, Andhra University for financial support.